Chemotaxonomic patterns in the distribution of amino acids of Hymenolepis palmarum (Johri, 1956) and other hymenolepidids revealed the common presence of beta-aminoisobutyric acid, lysine, phenylalanine and tyrosine but 3,4 dihydroxyphenylalanine and norleucine were exclusive to H. palmarum. Both qualitative and quantitative differences in amino acids have been recorded.